Wireless communications devices such as the BlackBerry® by Research in Motion Limited enable users to download map content from web-based data sources such as BlackBerry Maps™, Google Maps™ or Mapquest™. Downloaded map content is displayed on a small LCD display screen of the wireless communications device for viewing by the user. The user can pan up and down and side to side as well as zoom in or out. Due to the small display and limited processor on the device and due to the limited over-the-air (OTA) bandwidth, there is a need to optimize the delivery and handling of the map data.
With the increasing availability of wireless communications devices having onboard Global Positioning System (GPS) receivers for providing location-based services (LBS), the efficient delivery and handling of map data is increasingly important.
Pre-processing map data server-side to find ideal locations for labels is generally not a feasible solution for wireless communications devices because the label positions are specific to a particular zoom level. Transmitting pre-rendered bitmaps having label positions specific to each zoom level is too much of a burden on the limited over-the-air bandwidth. Even when the map data is in vector format, determining label positions server-side and then sending the coordinates to the wireless device is an unsatisfactory solution because of the resulting burden on the wireless link.
When performed on the client device, labelling map features in a computationally efficient manner on the small display screen is a challenge. Although complex algorithms can be devised to recursively test map label positions before rendering these in real-time on the map in a visually pleasing manner, the limited processing capacity make these complex algorithms generally unsuitable for use on wireless communications devices.
Accordingly, a technique for efficiently determining label positions for labels of maps displayed on wireless communications devices remains highly desirable.
It will be noted that throughout the appended drawings, like features are identified by like reference numerals.